This invention relates to manufacturing of stators for electric motors and in particular to a method and apparatus for preforming and final forming stator coil end turns. Stators for electric motors are conventionally manufactured by constructing a stator core lamination stack, winding one or more sets of coils and inserting these coils through the stator bore into the stator slots. After insertion of the coils into the stator core the return ends of the coils extend out of the stator slots and beyond the ends of the stator core. For reasons of appearance as well as customer specifications, the coil ends need to be shaped into a particular desired configuration. Such shaping operations are conventionally referred to as forming or blocking operations and conventionally have included a preforming operation wherein the wire was moved out of the extended bore of the stator and a final forming operation in which the end wires were shaped into the desired configuration. In the past, the preforming and final forming operations consisted of two distinct operations wherein, during the preforming operation, a preforming arbor was inserted into and extended through the bore of the stator to push the wires back from the extended stator bore. After this preforming operation the stator was transferred to another machine for final forming of the wire.
It is therefore desired to provide a method and apparatus for both preforming and final forming of stator coil end turns in one continuous set of operations in a single station.
A further problem with the prior art final forming operation has been that the coil end turn wires tended to be pinched by the outer diameter jaws as these jaws were positioned around the end turns. Such pinching was likely to damage the wire on the wire insulation. It is therefore desired to provide a final forming apparatus which does not pinch the coil end turn wires.